1. Field of the Invention
The present invention relates to an apparatus for forming a hardback book cover (a rigid cover) in hardback bookbinding, especially, in simple hardback bookbinding in which a hardback book is bounded by adhesive binding.
2. Description of the Related Art
A conventional hardback book is manufactured as a casebound book by attaching a rigid cover after applying a thread stitching to the spine of a book block, however, recently, the hardback book is also manufactured by attaching a rigid cover to the book block whose spine is preliminarily bounded by adhesive.
FIG. 16 is an exploded perspective view of a hardback book manufactured by a simple hardback bookbinding. Referring to FIG. 16, the hardback book is composed of a book block 50 whose spine is preliminarily bounded by adhesive, and a rigid cover 51 attached to the spine of the book block 50. The rigid cover 51 is composed of a cover 52 having a cardboard stiffener. In this case, a first cardboard 53 forming a front book cover, a second cardboard 54 forming a back book cover, and a third cardboard 55 forming the spine are attached to predetermined positions on the rear face of the cover 52, and an outer margin of a predetermined width is formed outside the cardboards 53 to 55 (a region forming top and bottom edges of the hardback book cover and a region forming front and back edges of the hardback book cover). Further, the outer margin is folded and attached to the cardboards 53 to 55, thereby the rigid cover 51 is formed.
Fold lines 52a and 52b are formed respectively between the first cardboard 53 and the third cardboard 55, and between the second cardboard 54 and the third cardboard 55. The third cardboard 55 is attached to the spine of the book block 50, the first cardboard 53 is attached to a front side end leaf paper 50a of the book block 50, and the second cardboard 54 is attached to a rear side end leaf paper 50b of the book block 50, so that the hardback book is manufactured.
In the case of forming the hardback book cover as mentioned above, it is necessary to fold the outer margins of four sides of the cover so as to attach them to the cardboards. However, since this work is carried out per one side of the cover by using a single folding unit, it takes a long working hour, and there is a problem that an efficiency is poor.
In addition, in the case of forming a hardback book cover whose corners are cut at 45 degrees, an additional work of folding edges for forming the cut corners is required, and there arises a problem of taking a long time to work.